各位大大好，目前在研究AES256加密上遇到問題

需求是在網頁的Javascript進行資料加密
傳給下一個網頁，由後台(VB.Net進行解密)

為了達成上面的需求，
先將Javascript和VB.Net各自加密同一個字串(Hello Word!!)
但結果不相同，不曉得是什麼問題，請大大們協助
(不太會排版，請大大們海涵)

Javascript

var mKey = '1234567812345678', mIV = '1234567812345678';
function Encrypt() {
    var word = "Hello World!!"; 
	var key = CryptoJS.enc.Utf8.parse(mKey);
	var iv = CryptoJS.enc.Utf8.parse(mIV);
	var srcs = CryptoJS.enc.Utf8.parse(word);
	var encrypted = CryptoJS.AES.encrypt(srcs, key, { iv: iv, mode: CryptoJS.mode.CBC, padding: CryptoJS.pad.Pkcs7 });
	return encrypted.ciphertext.toString().toUpperCase();
}

結果是 : AF938836C04E84558A4963C491E42B72

VB.Net

Private mSecretKey As String = "1234567812345678"
Private mIVKey As String = "1234567812345678"
Public Function EncryptAES256(ByVal source As String) As String
    Dim _source As String="Hello World!!" 
    Dim _aes = New RijndaelManaged()
    _aes.Key = Encoding.UTF8.GetBytes(mSecretKey)
    _aes.IV = Encoding.UTF8.GetBytes(mIVKey)
    _aes.Mode = CipherMode.CBC
    _aes.Padding = PaddingMode.PKCS7
    Dim _trans As ICryptoTransform = _aes.CreateEncryptor()

    Dim _srcBytes As Byte() = Encoding.UTF8.GetBytes(_source)
    Dim _outputData As Byte() = _trans.TransformFinalBlock(_srcBytes, 0, _srcBytes.Length)

    Return Convert.ToBase64String(_outputData)
End Function

結果是 : r5OINsBOhFWKSWPEkeQrcg==

如果以VB.Net為主的話，Javascript要如何修正呢?